Friends?

This past week, I have been pondering friendship. I don't have one of those " we've been friends since childhood, or the "your no longer a friend, your family". I've never had someone that close as a friend.
While going through this thinking I came to the point of a "friend purge" on my social media. I unfriended and unfollowed to the point of being down to 42 followers in Instagram. Why is it, that even if we slightly know someone, we want to follow their life as if we are personal friends. I eliminated 25 people, just off Instagram, that I was keeping up with, that I had only met once and would probably never meet again.
So the question that drives this post is, what is true friendship? I know it's not a Facebook following. It's not you liking all of my Instagram posts. It's not a call twice a year even! To me, friendship is being there for each other when you have no one else to talk to. When your going through a tough time and you need a shoulder to cry on. When no one else cares, that person is there for you. They keep your secrets, and you keep theirs.
Any relationship, has time invested. Friendship had a lot of this element! If you want to be called my friend, you must have had many hours with me to the point of you knowing me really well. Don't call me your friend if I don't know your favorites. Don't call me your friends if we never talk. And Please! Don't get mad if I tell you we are just acquaintances on account of any one of these things being left out.